Extract end-to-end integration testing framework

Description

We currently have two GitLab QA parts.

The first part is gitlab-qa project, a gem and a environment orchestration tool.

The second part is qa/ directory in CE / EE repositories, that include instance test scenarios.

Both parts share a few design concepts, thus the solution would benefit from sharing the same code as well.

Proposal

Possible solutions:

• Move common support files for handing scenarios, entrypoints, docker-related things to gitlab/qa/support and make it possible to boundle gem 'gitlab-qa' in qa/ specs + require 'gitlab-qa/support.

• Extract a separate gem that would help others to build an automated, click-driven QA solution.

Framework

Extracting support code to a separate gem / framework will allow other people to use it too.